A debugging support program causes a computer to execute: a step of extracting, from a module program constituting a sequence program, a first variable assigned to an input to the module program and a second variable assigned to an output from the module program; a step of creating a verification item for verifying operation of the module program, the verification item including a first setting value set for the first variable and a second setting value set for the second variable; a step of verifying operation of the module program based on the verification item; and a step of outputting a result of verifying operation of the module program.